#app .left {
    position: relative;
}

.message {
    position: absolute;
    top: 0;
    left: 0;
    z-index: 1000;
    background-color: rgba(0,0,0,.5);
    width: 100%;
    height: 100%;
}
.message-box {
    width: 300px;
    height: 150px;
    background-color: #fff;
    border-radius: 10px;
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%,-50%);
}   
.message .btn-close {
    position: absolute;
    right: 10px;
    top: 10px;
    color: #f00;
    cursor: pointer;
    font-size: 16px;
}
.message p {
    padding: 50px 15px;
    text-align: center;
}